An autonomous working system, an autonomous vehicle and a turning method thereof

ABSTRACT

Disclosed in the present invention is an autonomous vehicle ( 1 ), which comprises an housing ( 21 ), an driving module mounted on the housing ( 21 ), an borderline detecting module mounted on the housing for detecting the distance between the autonomous vehicle ( 1 ) and the borderline ( 3 ), an energy module mounted on the housing for providing energy for the autonomous vehicle, and an control module electrically connected with the driving module and the borderline detecting module. The control module controls the driving module to perform steering based on the signal representing the angle relationship between the autonomous vehicle ( 1 ) and the borderline ( 3 ) transmitted from the borderline detecting module, so that the axis ( 33 ) of the autonomous vehicle ( 1 ) always forms an acute angle or an right angle with one side of the borderline ( 3 ) while steering is completed, but another side of the borderline ( 3 ) forms an acute angle or an right angle with the core axis ( 33 ) of the autonomous vehicle ( 1 ) when the turning begins. The turning has directivity, so that the autonomous vehicle more easily goes out from the narrow area and the efficiency of area covering is higher; moving is kept during the turning, so that the energy is saved, and the working efficiency is improved.

TECHNICAL FIELD

The present invention relates to the field of smart control, inparticular to an autonomous vehicle, an autonomous working system and aturning method for the autonomous vehicle.

DESCRIPTION OF THE RELATED ART

Along with the continuous development of the computer technology andartificial intelligence technology, autonomous working systems similarto the intelligent robots have slowly enter people's life. Sumsung,Electrolux, and other company have both developed fully autonomous dustcollectors and put into the market. Those fully autonomous dustcollectors are usually small and integrated with an environment sensor,a self-driving system, a dust collection system, a battery and acharging system, can autonomously cruise in the room without operationby people, return to the dock to be docked and charged when the powerlevel is low, and then continue to cruise collector dust. Meanwhile,Husqvarna AB and other companies have developed the similar robot mowerscapable of autonomously cutting grasses on the lawn and charging withoutinference by users. Those autonomous working systems need no managementafter one-time setup, so users are deliberated from tedioustime-and-energy-consuming houseworks such as cleaning and lawnmaintenance and therefore are well welcome.

Those autonomous working systems all need precise cooperation of aplurality of systems and technologies during normal working, and pathplanning is one of the key technologies. The path planning technology isused for guiding the autonomous vehicle to select the path to move inthe working scope. Path planning needs to reduce the repeated movingtime and cover the working area as much as possible, and also need tocope with various complicated terrain and leave away smoothly whilekeeping a coverage rate in narrow areas, dead corners or obstacle areas.It can be said that path planning directly determines the workingefficiency of the autonomous vehicle. Poor path planning results inproblems when the autonomous vehicle is working, such as insufficientcoverage scope, dead corner, long time for covering the whole workingscope, or being captured in some special terrains.

At present, coverage and smoothly passing the narrow areas or deadcorners are the major technical problems encountered by path planning ofthe autonomous vehicle. The majority of the commercial autonomousworking systems all adopt random paths during moving, namely movingstraightly in the working scope, brake and stop moving first whenencountering obstacles, make a turn randomly or according to apredetermined program, and then start to move away. The autonomousworking devices can only sense that they encounter an obstacle or aborder, cannot know the original moving direction thereof and theaccurate position in the working area, fail to rationally judge whichdirection of turn is the optical scheme, therefore move randomly in anarrow area and need a long time to leave the area, and even fail toleave the area. Meanwhile, because of failing to judge the direction ofturn in the next step, the autonomous working devices are required tostop moving and then make a turn instead of directly making a turn.Moreover, the working area of the household autonomous working devicesis not big, and the autonomous working devices can quickly move from oneend to the other end and therefore need starting and stopping frequentlyin the whole working process. Those autonomous vehicles cannot movecontinuously and waste a lot of time on stop and startup, therebyreducing the overall moving speed, lowering the working efficiency,increasing the mechanical wear of the autonomous vehicle and shorteningthe service life.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide an autonomous vehiclewhich selects the turning path rationally and efficiently, a rationaland highly efficient turning method of an autonomous vehicle, and anautonomous working system for the autonomous vehicle. The presentinvention provides an autonomous vehicle for moving and working in aworking scope limited by the limit, comprising: a housing having alongitudinal central axis; a driving module mounted on said housing,said driving module drives said autonomous vehicle to move and make aturn, and comprises a wheel set and a driving motor for driving thewheel set to move; a limit detecting module mounted on said housing fordetecting a location relationship between said autonomous vehicle andsaid limit, an energy module mounted on the housing for providing energyfor said autonomous vehicle, and an control module electricallyconnected with said driving module and said limit detecting module;wherein: said control module controls said driving module to performturning based on a signal representing said angle relationship betweensaid autonomous vehicle and said limit transmitted from said limitdetecting module, so that said central axis of said autonomous vehiclealways forms an acute angle or a right angle with one side of said limitwhen said turn is completed, but another side of said limit forms anacute angle or a right angle with said central axis said the autonomousvehicle when said turn begins.

Preferably, said driving module drives said autonomous vehicle to make aturn in a direction where the acute angle or right angle between thecentral axis or limit is reduced.

Preferably, the angle of said turn is less than 180 degrees.

Preferably, the angle of said turn is greater than or equal to 90degrees.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing.

Preferably, said border sensing elements are arranged symmetrically withrespect to said central axis.

Preferably, said border sensing elements located on the front portion ofsaid housing.

Preferably, said border sensing elements are inductors.

Preferably, said predetermined location relationship is that one of saidborder sensing elements reaches a predetermined distance from saidlimit.

Preferably, said predetermined location relationship is that one of saidborder sensing elements is outside of said limit.

Preferably, the angle relationship is that the angle between saidcentral axis and any side of the limit starting from the intersectionpoint of the central axis and said limit is a right angle or an acuteangle or an obtuse angle.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of the central axis ofthe housing; when a border sensing element on one side sends a signal tosaid control module representing that it reaches a predetermineddistance to said limit, said control module determines that said limitlocated on one side of the central axis forms an acute angle with saidcentral axis.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, when a border sensing element at one side send a signal tosaid control module representing that it is outside of said limit first,said control module determine that said limit located at said one sideof said central axis forms an acute angle with said central axis.

Preferably, said angle relationship is that the angle value between saidcentral axis and any one of the two side start from the intersection ofsaid central axis and the limit.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, said control module records a move distance of saidautonomous vehicle in the time interval between said border sensingelements respectively sending a signal representing that it reach apredetermined distance from said limit, and calculates the angle betweensaid central axis and said border.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, said control module records a move distance of saidautonomous vehicle in the time interval between said border sensingelements respectively sending a signal representing that it is out ofsaid limit, and calculates an angle between said central axis and saidborder.

Preferably, the autonomous vehicle is a robot mover, also comprising acutting assembly located below the housing and a cutting motor drivingthe cutting assembly.

Preferably, the autonomous vehicle keeps moving from moving towards thelimit and reaching the predetermined location relationship to completingthe turn.

Preferably, the autonomous vehicle moves by a distance along the limitafter the turn begins and before the turn is completed.

The present invention also discloses an autonomous working system,comprising a limit for limiting the working scope of the autonomousworking system, and also comprising the mentioned autonomous vehicle.

Preferably, the limit comprises a border line signal generating elementand a border line in connection with the border line signal generatingelement. The border line signal generating element sends periodicalcurrent signals to the border line.

The present invention also discloses a turning method of an autonomousvehicle. The autonomous vehicle is used for moving and working in aworking scope limited by the limit. The turning method comprises thefollowing steps: the autonomous vehicle moves to the limit; theautonomous vehicle detects the location relationship with the limit;when reaching a predetermined location relationship with the limit, theautonomous vehicle detects the angle relationship with the limit,wherein the limit is divided into two sides start from the intersectionof the axis; the autonomous vehicle makes a turn to move away from thelimit so that the axis of the autonomous vehicle forms an acute angle ora right angle with one side of the border line while the turn iscompleted, but the other side of the limit forms an acute angle or aright angle with the axis of the autonomous vehicle when the turnbegins.

Preferably, the autonomous vehicle makes a turn to the direction whereinthe acute angle or right angle between the axis and the limit isreduced.

Preferably, the autonomous vehicle moves by a distance along the limitafter the turn begins and before the turn is completed.

Preferably, the autonomous vehicle moves by a predetermined time orpredetermined distance along the limit after the turn begins and beforethe turn is completed.

Preferably, the predetermined distance is between 20 cm and 100 cm.

Preferably, the autonomous vehicle has border sensing elementsrespectively on the two sides of the axis, said predetermined locationrelationship is that one of the border sensing elements reaches apredetermined distance from the limit, said method sensing the anglerelationship between the autonomous vehicle and the limit furthercomprises the following steps: the border sensing element on one side ofthe autonomous vehicle sends a collision signal to the control module ofthe autonomous vehicle after sensing that it reaches the predetermineddistance; the border sensing element on the other side of the autonomousvehicle sends a collision signal to the control module of the autonomousvehicle after sensing that it reaches the predetermined distance; andthe control module judges that the side on which the border sensingelement senses that it reaches the predetermined distance first forms anacute angle with the limit.

Preferably, said autonomous vehicle has border sensing elementsrespectively on the two sides of said central axis, said predeterminedlocation relationship is that one of said border sensing elements isoutside of said limit, said step sensing the angle relationship betweensaid autonomous vehicle and said limit further comprises followingsteps: said border sensing element on one side of said autonomousvehicle sends a collision signal to a control module of said autonomousvehicle when sensing that it is outside of said limit; said bordersensing element on the other side of the autonomous vehicle sends acollision signal to said control module of said autonomous vehicle whensensing that it is outside of said limit; said control module judgesthat the side on which said border sensing element senses that it isoutside of said limit first forms an acute angle with said limit.

Preferably, said autonomous vehicle has border sensing elementsrespectively on the two sides of said central axis, said predeterminedlocation relationship is that one of said border sensing elementsreaches a predetermined distance, said step sensing the anglerelationship between said autonomous vehicle and said limit furthercomprises following steps: said border sensing element on one side ofsaid autonomous vehicle detects that it reaches said predetermineddistance first sends a collision signal to a control module of saidautonomous vehicle; said autonomous vehicle keeps moving, said bordersensing element on the other side of the autonomous vehicle sends acollision signal to said control module of said autonomous vehicle whensensing that it reaches said predetermined distance; sensing the movingdistance of the autonomous device in the time that the two bordersensing elements reach the predetermined distance successively;calculating the value of included angle between said central axis of theautonomous vehicle and said limit according to the moving distance andthe distance between two border sensing elements when reaching saidpredetermined distance.

Preferably, said autonomous vehicle has border sensing elementsrespectively on the two sides of said central axis, said predeterminedlocation relationship is that one of said border sensing elements isoutside of said limit, said step sensing the angle relationship betweensaid autonomous vehicle and said limit further comprises followingsteps: said border sensing element on one side of said autonomousvehicle detects that it is outside of said limit first sends a collisionsignal to a control module of said autonomous vehicle; said autonomousvehicle keeps moving, said border sensing element on the other side ofthe autonomous vehicle sends a collision signal to said control moduleof said autonomous vehicle when sensing that it is outside of saidlimit; sensing a moving distance of said autonomous vehicle in the timethat said two border sensing elements is outside of said limitsuccessively; calculating the value of included angle between saidcentral axis of said autonomous vehicle and said limit according to themoving distance and the distance between two border sensing elementswhen is outside of said limit.

Preferably, the angle of said turn is greater than or equal to 90degrees, less than 180 degrees.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising a housing, adriving module, a limit detecting module, an energy module and a controlmodule, wherein the housing has a longitudinal axis; the driving moduleis mounted on the housing, drives the autonomous vehicle to move andmake a turn, and comprises a wheel set and a driving motor for drivingthe wheel set to move; the limit detecting module detects the locationrelationship between the autonomous vehicle and the limit; the energymodule is mounted on the housing for providing energy for the autonomousvehicle; and the control module is electrically connected with thedriving module and the limit detecting module. The autonomous vehiclemakes a turn to moves away from the limit after moving towards the limitand reaching a predetermined location relationship. In the predeterminedlocation relationship, the limit is divided into two sides by the pointof intersection with the central axis. The control module drives thedriving module to perform turning based on the signal representing theangle relationship between the autonomous vehicle and the limit from thelimit detecting module, so that the driving module drives the autonomousvehicle to make a turn in a direction where the acute angle or rightangle between the central axis or limit is reduced.

Preferably, the central axis of the autonomous vehicle always forms anacute angle or a right angle with one side of the limit when the turn iscompleted, and the other side of the limit forms an acute angle or rightangle with the central axis of the autonomous vehicle when the turnsbegins.

The present invention also provides a turning method of an autonomousvehicle. The autonomous vehicle is used for moving and working in aworking scope limited by the limit. The turning method comprises thefollowing steps: the autonomous vehicle drives to the limit; theautonomous vehicle detects the location relationship between it and thelimit; the autonomous vehicle detects the angle relationship with thelimit when the autonomous vehicle and the limit reach a predeterminedlocation relationship; and the autonomous working device make a turn inthe direction where the acute angle or right angle between the centralaxis and the limit is reduced.

Preferably, the limit is divided into two sides by the point ofintersection with the central axis when the autonomous vehicle and thelimit reach a predetermined location relationship; the central axis ofthe autonomous vehicle always form an acute angle or a right angle withone side of the limit when the turn is completed, while the other sideof the limit forms an acute angle or right angle with the central axisof the autonomous vehicle when the turn begins.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising a housing, adriving module, a limit detecting module, an energy module and a controlmodule, wherein the housing has a longitudinal axis and is divided intotwo sides by the central axis, namely left side and right side; thedriving module is mounted on the housing, drives the autonomous vehicleto move and make a turn, and comprises a wheel set and a driving motorfor driving the wheel set to move; the limit detecting module detectsthe location relationship between the autonomous vehicle and the limit;the energy module is mounted on the housing for providing energy for theautonomous vehicle; and the control module is electrically connectedwith the driving module and the limit detecting module. The autonomousvehicle makes a turn to moves away from the limit after moving towardsthe limit and reaching a predetermined location relationship. When theautonomous vehicle reaches the predetermined location relationship, thecontrol module drives the driving module to perform turning based on thesignal transmitted from the limit detecting module that represents oneside of the autonomous vehicle closer to the limit, so that the distancefrom one side of the autonomous vehicle to the limit is always smallerthan that from the other side to the limit.

Preferably, the autonomous vehicle makes a turn clockwise if the leftside is closer to the limit when reaching the predetermined locationrelationship; and the autonomous vehicle makes a turn anticlockwise ifthe right side is closer to the limit.

Preferably, the angle of said turn is greater than or equal to 90degrees, less than 180 degrees.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of the central axis ofthe housing.

Preferably, said border sensing elements are arranged symmetrically withrespect to said central axis, located on the front portion of saidhousing.

Preferably, said predetermined location relationship is that one of theborder sensing elements reaches a predetermined distance from the limit.

Preferably, said predetermined location relationship is that one of saidborder sensing elements is outside of said limit.

Preferably, when a border sensing element at one side send a signal tosaid control module representing that it reach a predetermined distancefrom said limit first, the control module determine that said one sideis closer to said limit.

Preferably, when a border sensing element at one side send a signal tosaid control module representing that it is out of the limit first, thecontrol module determine that said one side is closer to said limit.

Preferably, the autonomous vehicle is a robot mover, also comprising acutting unit located below the housing and a cutting motor driving thecutting unit to cut.

Preferably, the autonomous vehicle keeps moving from moving towards thelimit and reaching the predetermined location relationship to completingthe turn.

Preferably, the autonomous vehicle moves by a distance along the limitafter the turn begins and before the turn is completed.

The present invention also provides an autonomous working system,comprising a limit for limiting the working scope of the autonomousworking system, and also comprising the mentioned autonomous vehicle.

Preferably, the limit comprises a border line signal generating elementand a border line in connection with the border line signal generatingelement. The border line signal generating element sends periodicalcurrent signals to the border line.

The present invention also provides a turning method of an autonomousvehicle. The autonomous vehicle has a central axis which divides theautonomous vehicle into two sides, namely left side and right side. Theturning method comprises the following steps: the autonomous vehiclemoves towards the limit; the autonomous vehicle monitors the locationrelationship with the limit; the autonomous vehicle judges which side iscloser to the limit when reaching a predetermined location relationship;the autonomous vehicle makes a turn and moves away from the limit, sothat the distance from one side of the autonomous vehicle to the limitis always smaller to that from the other side to the limit, while oneside is closer to the limit when the turn begins.

Preferably, when reaching the predetermined location relationship, theautonomous vehicle makes a turn clockwise if the left side is closer tothe limit and makes a turn anticlockwise if the right side is closer tothe limit.

Preferably, the autonomous vehicle moves by a distance along the limitafter the turn begins and before the turn is completed.

Preferably, the autonomous vehicle moves by a predetermined time orpredetermined distance along the limit after the turn begins and beforethe turn is completed.

Preferably, the angle of said turn is greater than or equal to 90degrees, less than 180 degrees.

Preferably, the autonomous vehicle has border sensing elementsrespectively on the two sides of the axis, said predetermined locationrelationship is that one of the border sensing elements reaches apredetermined distance from the limit.

Preferably, the step that the autonomous vehicle judges which side iscloser to the limit comprises: when a border sensing element at one sidesend a signal to said control module representing that it reach apredetermined distance from said limit first, the control moduledetermine that said one side is closer to said limit.

Preferably, said autonomous vehicle has border sensing elementsrespectively on the two sides of said central axis, said predeterminedlocation relationship is that one of said border sensing elements isoutside of said limit.

Preferably, the step that the autonomous vehicle judges which side iscloser to the limit comprises: when a border sensing element at one sidesend a signal to said control module representing that it is outside ofsaid limit first, the control module determine that said one side iscloser to said limit.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising a housing, adriving module, a limit detecting module, an energy module and a controlmodule, wherein the housing has a longitudinal axis and is divided intotwo sides by the central axis, namely left side and right side; thedriving module is mounted on the housing, drives the autonomous vehicleto move and make a turn, and comprises a wheel set and a driving motorfor driving the wheel set to move; the limit detecting module detectsthe location relationship between the autonomous vehicle and the limit;the energy module is mounted on the housing for providing energy for theautonomous vehicle; and the control module is electrically connectedwith the driving module and the limit detecting module. The autonomousvehicle makes a turn to moves away from the limit after moving towardsthe limit and reaching a predetermined location relationship. When theautonomous vehicle reaches the predetermined location relationship, thecontrol module drives the driving module to perform turning based on thesignal transmitted from the limit detecting module that represents oneside of the autonomous vehicle closer to the limit, the autonomousvehicle makes a turn clockwise if the left side is closer to the limitwhen reaching the predetermined location relationship; and theautonomous vehicle makes a turn anticlockwise if the right side iscloser to the limit.

Preferably, when the turn is completed, the distance from one side ofthe autonomous vehicle to the limit is always smaller than that from theother side to the limit.

The present invention also provides a turning method of an autonomousvehicle. The autonomous vehicle has a central axis which divides theautonomous vehicle into two sides, namely left side and right side. Theturning method comprises the following steps: the autonomous vehiclemoves towards the limit; the autonomous vehicle monitors the locationrelationship with the limit; the autonomous vehicle judges which side iscloser to the limit when reaching a predetermined location relationship;the autonomous vehicle makes a turn and moves away from the limit, theautonomous vehicle makes a turn clockwise if the left side is closer tothe limit when reaching the predetermined location relationship; and theautonomous vehicle makes a turn anticlockwise if the right side iscloser to the limit.

Preferably, when the turn is completed, the distance from one side ofthe autonomous vehicle to the limit is always smaller to that from theother side to the limit, while one side is closer to the limit when theturn begins.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising a housing, adriving module, a limit detecting module, an energy module and a controlmodule, wherein the housing has a longitudinal axis and is divided intotwo sides by the central axis, namely left side and right side; thedriving module is mounted on the housing, drives the autonomous vehicleto move and make a turn, and comprises a wheel set and a driving motorfor driving the wheel set to move; the limit detecting module detectsthe location relationship between the autonomous vehicle and the limit;the energy module is mounted on the housing for providing energy for theautonomous vehicle; and the control module is electrically connectedwith the driving module and the limit detecting module. Said autonomousvehicle receives the signal representing said location relationshipbetween said autonomous vehicle and said limit from said limit detectingmodule, said control module controls the driving module to make a turnto leave said limit, said autonomous vehicle keeps moving from movingtowards the limit and reaching the predetermined location relationshipto completing the turn.

Preferably, the driving motor drives the driving wheel to movecontinuously from that the autonomous vehicle and the limit reach thepredetermined location to that the turn is completed.

Preferably, the control module controls the driving module to performturning based on the signal representing the angle relationship betweenthe autonomous vehicle and the limit transmitted from the limitdetecting module, so that the central axis of the autonomous vehiclealways form an acute angle or a right angle with one side of the limitwhen the turn is completed, while the other side of the limit forms anacute angle or right angle with the central axis of the autonomousvehicle when the turn begins.

Preferably, the control module controls the driving module to performturning based on the signal representing the angle relationship betweenthe autonomous vehicle and the limit transmitted from the limitdetecting module, and the driving module makes a turn towards thedirection where the acute angle or right angle formed by the axis andthe limit is reduced.

Preferably, the angle relationship is that the angle between the centralaxis and the central axis and any side of the limit starting from theintersection point of the central axis and the limit is an right angleor an acute angle or an obtuse angle.

Preferably, the limit detecting module comprises border sensing elementsrespectively located on the two sides of the central axis of thehousing; after a border sensing element on one side sends a signal tothe control module representing that it reaches a predetermined distanceto the limit, the control module determines that the limit located onone side of the central axis forms an acute angle with the central axis.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, when a border sensing element at one side send a signal tosaid control module representing that it is outside of said limit first,said control module determine that said limit located at said one sideof said central axis forms an acute angle with said central axis.

Preferably, said angle relationship is that the angle value between saidcentral axis and any one of the two side start from the intersection ofsaid central axis and the limit.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, said control module records a move distance of saidautonomous vehicle in the time interval between said border sensingelements respectively sending a signal representing that it reach apredetermined distance from said limit, and calculates the angle betweensaid central axis and said border.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing, said control module records a move distance of saidautonomous vehicle in the time interval between said border sensingelements respectively sending a signal representing that it is out ofsaid limit, and calculates an angle between said central axis and saidborder.

Preferably, when the autonomous vehicle reaches the predeterminedlocation relationship, the control module drives the driving module toperform turning based on the signal transmitted from the limit detectingmodule that represents one side of the autonomous vehicle closer to thelimit, so that the distance from one side of the autonomous vehicle tothe limit is always smaller than that from the other side to the limit.

Preferably, when the autonomous vehicle reaches the predeterminedlocation relationship, the control module drives the driving module toperform turning based on the signal transmitted from the limit detectingmodule that represents one side of the autonomous vehicle closer to thelimit, the autonomous vehicle makes a turn clockwise if the left side iscloser to the limit when reaching the predetermined locationrelationship; and the autonomous vehicle makes a turn anticlockwise ifthe right side is closer to the limit.

Preferably, said limit detecting module comprises border sensingelements respectively located on the two sides of said central axis ofsaid housing.

Preferably, said border sensing elements are arranged symmetrically withrespect to said central axis, located on the front portion of saidhousing.

Preferably, the angle of said turn is greater than or equal to 90degrees, less than 180 degrees.

Preferably, the autonomous vehicle is a robot mover, also comprising acutting assembly located below the housing and a cutting motor drivingthe cutting assembly.

The present invention also provides an autonomous working system,comprising a limit for limiting the working scope of the autonomousworking system, and also comprising the mentioned autonomous vehicle.

Preferably, the limit comprises a border line signal generating elementand a border line in connection with the border line signal generatingelement. The border line signal generating element sends periodicalcurrent signals to the border line, said border sensing elements areinductors.

The autonomous vehicle moves to the limit; the autonomous vehicledetects the location relationship with the limit; when reaching apredetermined location relationship with the limit, the autonomousvehicle makes a turn to move away from the limit, said autonomousvehicle keeps moving from moving towards the limit and reaching thepredetermined location relationship to completing the turn.

Preferably, the autonomous working system further comprises thefollowing procedure: when the autonomous vehicle and the limit reach apredetermined location relationship, the autonomous working systemdetects the angle relationship between the autonomous vehicle and thelimit, wherein the limit is divided into two sides.

Preferably, the autonomous working system further comprises thefollowing procedure: the autonomous working system detects the anglerelationship between the autonomous vehicle and the limit when theautonomous vehicle and the limit reach a predetermined locationrelationship, and makes a turn in a direction where the central axis andthe limit forms an acute angle or right angle.

Preferably, the angle of said turn is greater than or equal to 90degrees, less than 180 degrees.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising a housing, adriving module, a limit detecting module, an energy module and a controlmodule, wherein the housing has a longitudinal axis and is divided intotwo sides by the central axis, namely left side and right side; thedriving module is mounted on the housing, drives the autonomous vehicleto move and make a turn, and comprises a wheel set and a driving motorfor driving the wheel set to move; the limit detecting module detectsthe location relationship between the autonomous vehicle and the limit;the energy module is mounted on the housing for providing energy for theautonomous vehicle; and the control module is electrically connectedwith the driving module and the limit detecting module; after move tothe limit and reaches a predetermined location relationship, theautonomous vehicle makes a turn to move away from the limit, after theturn begins and before the turn is completed, said control modulecontrols the driving module to make the autonomous vehicle move alongthe limit for a distance.

Preferably, after the turn begins and before the turn is completed, saidcontrol module controls the driving module to make the autonomousvehicle move along the limit for a predetermined distance or apredetermined time.

Preferably, the predetermined distance is between 20 cm and 100 cm.

The control module drives the driving module to perform turning based onthe signal representing the angle relationship between the autonomousvehicle and the limit from the limit detecting module, so that thedriving module drives the autonomous vehicle to make a turn in adirection where the acute angle or right angle between the central axisor limit is reduced.

Preferably, said control module drives said driving module to performturning based on a signal representing said angle relationship betweensaid autonomous vehicle and said limit from said limit detecting module,so that said driving module drives the autonomous vehicle to make a turnin a direction where an acute angle or right angle between the centralaxis or limit is reduced.

Preferably, when the autonomous vehicle reaches the predeterminedlocation relationship, the control module drives the driving module toperform turning based on the signal transmitted from the limit detectingmodule that represents one side of the autonomous vehicle closer to thelimit, so that the distance from one side of the autonomous vehicle tothe limit is always smaller than that from the other side to the limit.

When the autonomous vehicle reaches the predetermined locationrelationship, the control module drives the driving module to performturning based on the signal transmitted from the limit detecting modulethat represents one side of the autonomous vehicle closer to the limit,the autonomous vehicle makes a turn clockwise if the left side is closerto the limit and makes a turn anticlockwise if the right side is closerto the limit.

Preferably, said autonomous vehicle keeps moving from moving towards thelimit and reaching the predetermined location relationship to completingthe turn.

Preferably, the autonomous vehicle is a robot mover, also comprising acutting assembly located below the housing and a cutting motor drivingthe cutting assembly.

The present invention also provides an autonomous working system,comprising a limit for limiting the working scope of the autonomousworking system, and also comprising the mentioned autonomous vehicle.

Preferably, the limit comprises a border line signal generating elementand a border line in connection with the border line signal generatingelement. The border line signal generating element sends periodicalcurrent signals to the border line; said limit detecting modulecomprises inductors for sensing said border line signal. Preferably,when the autonomous vehicle moves along the line, the control modulecontrols the driving module to keep the distance from the border sensingelements to the border lines unchanged.

Preferably, two border sensing elements are respectively located on twosides of the central axis. When autonomous vehicle moves along theborder line, one border sensing element is located within the borderline, while the other border sensing element is located out of theborder line. The control module controls the driving module to keep thedistances from the two border sensing elements to the border line equal.

The present invention also provides a turning method of an autonomousvehicle. The autonomous vehicle has a central axis which divides theautonomous vehicle into two sides, namely left side and right side. Theturning method comprises the following steps: the autonomous vehiclemoves towards the limit; the autonomous vehicle monitors the locationrelationship with the limit; when the autonomous vehicle reaching apredetermined location relationship with said limit, the autonomousvehicle makes a turn and moves away from the limit, and after the turnbegins and before the turn is completed, said control module controlsthe driving module to make the autonomous vehicle move along the limitfor a distance.

Preferably, the method further comprises following steps: the autonomousvehicle judges which side is closer to the limit when reaching apredetermined location relationship, when the turn is completed, thedistance from one side of the autonomous vehicle to the limit is alwayssmaller to that from the other side to the limit, while one side iscloser to the limit when the turn begins.

Preferably, the autonomous vehicle makes a turn clockwise if the leftside is closer to the limit when reaching the predetermined locationrelationship; and the autonomous vehicle makes a turn anticlockwise ifthe right side is closer to the limit.

The present invention also provides an autonomous vehicle for moving andworking in a working scope limited by the limit, comprising: a housinghaving a longitudinal central axis; a driving module mounted on saidhousing, said driving module drives said autonomous vehicle to move andmake a turn, and comprises a wheel set and a driving motor for drivingthe wheel set to move; a limit detecting module mounted on said housingfor detecting a location relationship between said autonomous vehicleand said limit, an energy module mounted on the housing for providingenergy for said autonomous vehicle, said control module is electricallyconnected with the driving module and the limit detecting module. Afterreceiving the collision signal, the control module drives the drivingmodule to bring the autonomous vehicle to make a turn and return backinto the border line. After receiving the collision signal again, thecontrol module records a numerical value representing the time intervalbetween the two collision signals or the moving distance, and if thenumerical value is greater than a first predetermined value, determinesthe turn is made in the direction where the obtuse angle between thecentral axis of the robot mower and the border line is reduced whencrossing the border line for the first the time.

Preferably, the number of the border sensing elements is one.

Preferably, the control module compares the numerical value with asecond predetermined value, determines the turn is made in the directionwhere the acute angle between the central axis of the robot mower andthe border line is reduced when crossing the border line for the firsttime if the numerical value is smaller than the second predeterminedvalue, and determines the turn is made in a direction where the rightangle between the central axis of the robot mower and the border line isreduced when crossing the border line for the first time if thenumerical value is between the first numerical value and the secondnumerical value.

Preferably, the first predetermined time is equal to the secondpredetermined time.

Preferably, when it is determined that the turn is made in the directionwherein the obtuse angle between the central axis of the robot mower andthe border line is reduced when crossing the border line for the firsttime, the control module controls the driving module to perform turningreversely until the central axis and the edge of the original obtuseangle that is located on the border line after the reverse turn.

The present invention also provides an autonomous working systemcomprising: border line with border signal for limit a working scope;border signal generator for sending border signal to said border line,said autonomous working system further comprising mentioned autonomousvehicle.

Preferably, said border signal generator sends periodical currentsignal.

The present invention also provides a turning method of an autonomousvehicle, said autonomous vehicle has a central axis, said methodcomprises following steps: move to a border line; cross and go outsidethe border line first time; make a turn to the inner side of the borderline; cross the border line second time; record the data representingthe time interval or moving distance between two collision signalrepresenting the two crosses; if the data is greater than a first presetvalue, then judge that said turn was toward a direction that reducing anobtuse angle between a central axis of said autonomous vehicle when itacross the border line first time.

Preferably, said method further comprising following steps: compares thedata with a second preset value, judges that the turn was towards thedirection that reduce the acute angle between the central axis and theborder line when the autonomous vehicle across the border line firsttime if said data is less than said second preset value; judges that theturn was towards the direction that reduce the right angle between thecentral axis and the border line when the autonomous vehicle across theborder line first time if said data is less than said second presetvalue.

Preferably, said method further comprising following steps: when judgingthat said turn was toward a direction that reducing an obtuse anglebetween a central axis of said autonomous vehicle when it across theborder line first time, said autonomous vehicle make a turn reverselyuntil that the central axis form an acute angle with the border linewhich forms an obtuse angle with the central axis before.

Compared with the prior art, the present invention has the beneficialeffects: the included angle between the autonomous vehicle keepingturning and the border line on the other side of the intersection pointis also an acute angle, or the turning to the working scope is completedat a small angle on the premise that the distance from one side of theautonomous vehicle approaching the border first to the limit is smallerthan that from the other side to the limit, so it is finally achievedthat the autonomous vehicle moves in a direction.

If the working scope is divided into two parts by the limit verticalline at the intersection point of the autonomous vehicle and the limit,the autonomous vehicle moves from one part to the other part afterturning instead of staying in the original part. In this way, theautonomous vehicle more usually moves to different areas and thereforeincreases the working scope coverage efficiency, and more easily movesout of the complicated area.

Moreover, the autonomous vehicle keeps moving when turning or fromapproaching the limit to leaving from the limit, or the driving motorkeeps driving the wheel set, thereby greatly improving the overallefficiency of the robot mower, increasing the efficiency, saving energy,protecting the environment, improving the service life of the battery,and cutting more grasses or doing more work in the unit battery time.

Statistically, the autonomous vehicle can do an extra work of 20% oncondition that the battery is full after the path planning mode isemployed, effectively using the inertia of the device itself andachieving an excellent energy-saving effect.

Meanwhile, in the working time, the work done by the autonomous vehicleemploying the method is 35% more than that of the autonomous vehicle notemploying the method, thereby greatly improving the working efficiency.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE ATTACHED DRAWINGS

FIG. 1 is the general view of the autonomous working system in thespecific embodiment of the present invention.

FIG. 2 is the general view of the robot mover system in the specificembodiment of the present invention.

FIG. 3 is the structural view of the specific embodiment of the presentinvention.

FIG. 4 is a path selecting diagram of the robot mower in the specificembodiment of the present invention.

FIG. 5 is a path selecting diagram of the robot mower in the specificembodiment of the present invention.

FIG. 6 is a path selecting diagram of the robot mower in the specificembodiment of the present invention.

FIG. 7 is a schematic view of the angle relationship between the robotmower and the border line before and after turning in the specificembodiment of the present invention.

FIG. 8 is a schematic view of the location relationship between the twosides of the robot mower and the border line before and after turning inthe specific embodiment of the present invention.

FIG. 9 is a schematic view of the turning of the robot mower by means ofa sensor in the specific embodiment of the present invention.

FIG. 10 is a path diagram of an autonomous vehicle in the prior artpassing through a narrow area.

FIG. 11 is a path diagram of the autonomous vehicle in the specificembodiment of the present invention that passes through the narrow area.

FIG. 12 is another path diagram of the autonomous vehicle in thespecific embodiment of the present invention that passes through thenarrow area.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The specific implementation of the present invention is described infurther detail with reference to the attached drawings.

As shown in FIG. 1, the autonomous working system in the embodiment ofthe present invention comprises an autonomous vehicle 1, a limit 3 and adock 5, wherein the limit 3 is used for limiting the working area 7 ofthe autonomous working system; the autonomous vehicle moves and workswithin or between the limit; and the dock is configured for supplyingdocking for the autonomous vehicle, in particular for supplying energyafter the autonomous vehicle returns to supplement energy.

Limit is the common name of borders and obstacles. The border is theperiphery of the whole working area, usually connected end to end toenclose the working area. The border may be a tangible body like a wall,fence, rail, etc., or electronically virtual signal border like anelectromagnetic signal or optical signal sent by the a border signalgenerator. The obstacle covers a part or an area where the autonomousvehicle cannot move in the working scope, such as sofas and besidetables in the room and pools and flower-stand out of the room.Similarly, the obstacle may also be tangible or electronically virtual.The tangible obstacles may be formed by the mentioned obstacles, whilethe electronic obstacles are formed by virtual obstacle signalstransmitted by the border signal generator. The virtual border signaland the virtual obstacle signal may be the same signal or differentsignals, upon the specific demands.

The autonomous vehicle may be a robot mower or an autonomous dustcollector, autonomously moving on the ground or surface within theworking area to mow grasses or collect dust. Of course, the autonomousvehicle is not limited to the robot mower and the autonomous dustcollector, and may be other devices such as spraying devices andmonitoring devices suitable for unmanned supervision.

The autonomous vehicle 7 comprises a driving module, a working module, alimit detecting module, an energy module, a control module, etc.

The driving module is used for driving the autonomous vehicle to move inthe working area 7, usually composed of a wheel set installed on theautonomous vehicle 7 and a driving motor for driving the wheel set tomove. The wheel set comprises driving wheels connected with the drivingmotor and auxiliary wheels for auxiliary support. Preferably, in theembodiment of the present invention, two driving wheels are located atthe rear portion of the autonomous vehicle 7, each connected with adriving motor; one or two auxiliary wheels are located at the front partof the autonomous vehicle.

The working module is used for executing the specific working tasks ofthe autonomous vehicle. If the autonomous vehicle 7 is an autonomousdust collector, the working module comprises a motor, a dust collectionopening, a dust collection pipe, a vacuum chamber, a dust collectingunit, and other working parts for executing the dust collection task; ifthe autonomous vehicle 7 is a robot mower, the working module comprisescutting blades, a cutting motor, and may also comprise parts foroptimizing or regulating the mowing effects such as a mowing heightregulator.

The limit detecting module is used for detecting the relative locationrelationship between the autonomous vehicle 7 and the limit 3, whereinthe relative location relationship specifically may comprise one orseveral of the distance, angle, and location in or out of the limit. Thelimit detecting modules may vary with compositions and principles, suchas the far infrared ray type, ultrasonic wave type, collision detectiontype, magnetic sensing type limit detecting modules; the location andquantity of the sensors and the corresponding signal generators are alsodiversified, related to the path planning mode. Therefore, theembodiment and path planning modes will be described in detail below.

The energy module is used for supplying energy for the autonomousvehicle 1 to complete various work, comprising a chargeable battery anda charging connection structure. The charging connection structureusually is a charging electrode exposed from the autonomous vehicle.

The control module is used for controlling the autonomous vehicle 1 toautonomously move and work. It is the core part of the autonomousvehicle 1, and functions thereof include controlling the working moduleto start working or stop, generating a moving path and controlling thedriving module to move along the moving path, judging the remainingenergy of the energy module and give instructions to the autonomousvehicle to return to the dock for charging, etc. The control moduleusually comprises a singlechip machine, a memory and other peripheralcircuits.

Except for the mentioned modules, the autonomous vehicle 1 alsocomprises a housing for accommodating and installing various modules, acontrol panel operated by a user, etc., and also comprises variousenvironmental sensors, such as the humidity sensor, temperature sensor,acceleration sensor, light sensor, etc. Those sensors can help theautonomous vehicle to judge the working environment to execute thecorresponding program.

The dock 5 is usually located within the working scope, beside the limit3 or on the limit 3, and connected with the commercial power or otherpower supply system for charging the autonomous vehicle. The dock 5 isprovided with a charging electrode for docking with the correspondingelectrode of the autonomous vehicle 1.

The following is the detail description of the path planning mode in theembodiment, in particular the way of leaving the limit and returningback into the limit, and the path planning mode for narrow areas wherethe common autonomous vehicles 1 have difficult in movement.

Before describing the path planning mode, the structure of a specificautonomous working system is introduced first, and lays a basis fordescribing various path planning modes. It should be noted that thespecific structure of the autonomous working system only are introducedfor uniform and convenient description, is not exclusive and can beappropriately changed, and some of the changes are described in detailin the following text.

As shown in FIG. 2, this autonomous working system is an autonomousmowing system. The autonomous mowing system comprises: a robot mower 11as the autonomous working system, a dock 5 for docking and charging therobot mower, a border signal for generating the border signal, and aborder line 13 connected with the border signal generator. The borderline 13 and the border signal generator form a closed ring. The borderline 13 has the border signal, and the working scope of the robot moweris formed within the border line 13.

The border signal generator periodically generates and sends electricsignals into the border line 13. The border line 13 is a lead on whichthe corresponding periodical current passes. The periodic currentgenerates a magnetic field periodically. The magnetic field hasdirection and intensity, in opposite direction on two sides of theborder line, namely in opposite direction toward and backward theworking scope, and the magnetic field signals become intense whenapproaching the border line.

Preferably, the periodical current signal is a square wave pulse signaleasily generated and identified, and can reduce cost and improveefficiency.

Also as shown in FIG. 2, an island 15 locates in the working scope. Theisland 15 is an area within the working scope, and the autonomousvehicle 1 shall not work there, but bypass it. The island 15 may be aflower-stand, a pool, etc. where the autonomous vehicle 1 cannot pass.In this autonomous mowing system, the island 15 is also surrounded bythe border line 13. As shown in the figure, the border line 13 extendsto the island 15 from an appropriate position of the border, surroundsthe island 15 in a circle, goes back to the starting point of the borderline, and then returns to the border along the border line 13. In thisway, the border signal exists on the periphery of the island 15, and therobot mower 15 will not enter the island 15, while the island 15 and theborder has two border lines 13 close to each other but opposite indirection. The currents on those two border lines 13 are opposite indirection, so the generated magnetic fields are counteracted. Due to noborder signal, the robot mower 11 can pass freely.

In this autonomous mowing system, the border line 13 is preferablyconfigured at a position at a distance from the actually physical limitof the area to be mowed, such as a position in a lawn at a distance of30 cm away from the edge of the lawn, or a position at a distance of 30cm away from the flower-stand in the island 15. This is because thelimit is a virtual signal and cannot physically block the robot mower11. Therefore, a distance of inertia movement is reserved for the robotmower 11, and the robot mower 11 still can move out at a certaindistance after monitoring the border line and does not leave the realworking scope.

Also as shown in FIG. 2, an obstacle 17 exists in the working scope, andspecifically may be an earth slope, a stone, a tree, etc. In this robotmower system, the similar obstacles do not form the island 15 by meansof the border line, but are detected by the obstacle sensor installed onthe robot mower 11.

FIG. 3 is a structural view of the robot mower of the robot mowersystem. As mentioned above, the autonomous vehicle comprises a housing21, and a driving module, a working module, a limit detecting module, anenergy module, a control module, etc. installed on the housing.

In this robot mower 11, the driving module comprises a wheel setinstalled below the housing. The wheel set comprises driving wheels. Twodriving wheels are respectively located on the two sides in the rear ofthe housing 21. The wheel set also comprises auxiliary wheels 25. Twoauxiliary wheels are respectively located on the two sides on the frontof the housing 21. The driving module also comprises a driving motorconnected with the driving wheels. The driving motor is responsible fordriving the driving wheels 23 to rotate to bring the robot mower 11 tomove and also responsible for driving the driving wheels 23 to performturning. In this robot mower 11, two driving wheels 23 are respectivelyconnected with a driving motor. The rotation speed of the driving motoris controlled by the control module. When the control module orders thetwo driving motor to rotate in the same direction at the same speed, therobot mower 11 moves along a straight line; when the control moduleorders the two driving motor to rotate at different speeds or indifferent directions, the robot mower 11 performs turning towards theside on which the driving wheels rotates at a slower speed or the sideon which the driving wheel goes back.

In the robot mower 11, the working module comprises a cutting module 29installed below the robot mower and a cutting motor 31 for driving thecutting module 29 to mow grasses. The cutting module 29 can be a bladeconnected to the mowing output shaft or a combination of a cutter and ablade connected to the mowing output shaft, and the specific structurethereof may be known for those skilled in the art and therefore is notdescribed in detail.

In the robot mower 11, the limit detecting module are border sensingelements 35 installed in the housing 21. Specifically, the robot mowerhas a longitudinal central axis 33. The central axis 33 drives thehousing 21 into two sides, namely left side and right side. The bordersensing elements 35 are electric inductors (inductors for short)respectively installed on two sides of the central axis 33. Preferably,two electric inductors are symmetrically installed on two sides of thecentral axis 33, at the front part of the housing 21. The advantage thatthe electric inductors are located at the front is that the bordersignal can be sensed more quickly and accurately. The limit detectingmodule is connected with the control module to transmit the monitoredborder signal to the control module. Of course, more the electricinductors also can be located in the middle part or rear part of thehousing 21 to increase the accuracy of the border signal identification.

In the robot mower 11, the energy module is a chargeable battery locatedin the housing 21, and a charging electrode connected with thechargeable battery. The charging electrode is located at the front partof the housing and exposed out of the housing 21 for docking with thecorresponding charging electrode of the dock 5 when the robot mower 11enters the dock 5 and charging the robot mower 11.

In the robot mower 11, the control module 11 is located in the housing21, comprising a microcontroller, a memory, etc. The memory is used forstoring the working programs of the robot mower and the relatedparameters of the robot mower in the working process, information fedback by other modules, etc. The microcontroller is used for receivingsignal sent from other systems and the programs built in the memory,performing calculation and sending corresponding working orders to themodules.

The robot mower 11 also comprises an obstacle monitoring module which isspecifically a collision sensor installed on the housing. When the robotmower 11 collides with an obstacle, the collision sensors detectcollision, generate collision signals and transmit the collision signalsto the control module.

The robot mower 11 also comprises a control panel for setting theworking mode by the operator. More details are not described here.

The working mode of the autonomous mowing system is briefly introducedbelow. The robot mower 11 cruises and mows grasses in the working scopesurrounded by the border line 13. In normal cases, the autonomous mower11 moves in a straight way until colliding with the limit, namely theborder line 13 or the obstacle 17. If collides with the border line 13or the obstacle, the robot mower 11 performs turning, returns back intothe limit, and keeps moving straightly until colliding with the limitagain. The robot mower 11 works in the whole working area 7 by thementioned way of continuously moving back in the limit. When the robotmower 11 reaches a predetermine lower level of power or is required tobe return back to the dock 5 because other situations occur, the controlmodule controls the robot mower 11 to seek the border line 13 and movealong the border line 13. The dock 5 is located on the border line 13,so the robot mower 11 moves back into the dock 5 along the border 13 andthen is docked and charged or berthed in the dock 5.

When the autonomous working system represented by the above mentionedautonomous mowing system works, turning back into the limit afterreaching the limit is the most frequent situation of work suspension,and improving the efficiency of turn will directly and greatly improvethe working efficiency of the autonomous working system.

Therefore, the way of leaving the limit and returning back into thelimit in the embodiment of the present invention is described first. Theautonomous vehicle 1 inevitably collides with the limit after moving fora period of time. When the autonomous vehicle 1 monitors that it reachesthe limit through the limit detecting module, the mutual relativelocation relationship is the mentioned angle relationship,interior-exterior relationship, angle relationship, etc. The limitdetecting module sends the signals such as the approach degree signaland/or angle relationship signal that represents those locationrelationships to the control module. The autonomous vehicle performsturning to move away from the limit after moving towards the limit andreaching a predetermined location relationship to ensure not leaving theworking scope. The signal received by the control module from the limitdetecting module may represent the angle relationship between theautonomous vehicle and the limit, the side of the autonomous vehicleclose to the limit, or several of the mentioned items. This depends onhow to interpret the signal sent from the limit detecting module.

The mentioned predetermined location relationship relates to the startupconditions of turning and other vary with the specific autonomousworking system. For example, in this robot mower system, thepredetermined location relationship is that the robot mower 11 has beenalready collided with the border line, while one electric inductor islocated directly above the border line 13, namely the distance from acertain border sensing element to the limit reaches 0 predetermineddistance. While in the autonomous dust collector system, the border isusually a wall, so the predetermined location relationship is usually adistance from the front end of the autonomous dust collector to theborder, such as 30 cm. Of course, those examples are schematic, and thepredetermined location relationship is set according to the specificdemands.

For the specific turning process, the central axis of the autonomousvehicle inevitably forms an intersection point with the limit, and inthe situation of not vertically approaching the limit, one side of theautonomous vehicle inevitably is closer to the limit. Then, when thecentral axis of the autonomous vehicle 1 forms an acute angle with theleft or right border line of the intersection point when it is notvertical to the limit, and the autonomous vehicle turning in thedirection where the acute angle is reduced can efficiently turn to thelimit at a relatively small angle. More abstractly speaking, theautonomous vehicle monitors the location relationship between it and thelimit, and the control module makes the driving module to performturning according to the signal representing the angle relationshipbetween the autonomous vehicle and the limit transmitted from the limitdetecting module, so the turning is quicker and more efficient. Thecontrol module makes the driving module to make a turn in the directionwhere the acute angle or right angle between the central axis and thelimit is reduced, and always keeps that the central axis of theautonomous vehicle always form an acute angle or a right angle with oneside of the limit, while the other side of the limit forms an acuteangle or right angle with the central axis of the autonomous vehiclewhen the turn begins. Similarly, the mentioned process can also beunderstood that the autonomous vehicle monitors the locationrelationship between it and the limit, judges which side of it is closerto the limit when reaching a predetermined location relationship withthe limit, and performs turning clockwise if the left side is closer tothe limit, otherwise performs turning anticlockwise if the right side iscloser to the limit; moreover, the turning result is always that thedistance from one side of the autonomous vehicle to the limit is smallerthan that from the other side to the limit, while said one side iscloser to the limit when the turn begins. The two descriptions aredifferent in mode, but consistent in nature. It should be understoodthat the signal parameters sent by the limit detecting module physicallycorrespond to different scenes.

FIG. 4, FIG. 5 and FIG. 6 are path selecting diagrams of the robot mower11 after reaching the limit. In FIGS. 4, 5 and 6, the moving directionof the robot mower 11 is identical, and the extension direction of thecentral axis 33 is identical when the robot mower collides with theborder line 13, but the extension direction of the border line 13 indifferent in the figures, so the turning direction and result aredifferent. In the figures, the dotted line passing through the robotmower 11 is the moving track of the robot mower 11.

In the robot mower system, at the moment when the robot mower 11collides with the border line 13, the central axis 33 of the robot mower11 forms an intersection point 41 with the border line 13, then centralaxis 33 forms an angle with each of the two border lines 13 of theintersection point 41, and the sum of the two angles is 180 degrees. Itshould be noted that the border lines 13 or the limit may be bent in anoverall view, but the border line 13 near an intersection point or thelimit may be regarded as a straight line; or it can be said that, theborder line 13 or the limit may be bent, but at the predetermineddistance for judging the turn, namely the intersection between thecentral axis 33 and the border line 13 or the limit, the border line 13or the limit is a straight line in the extension direction, and theextension direction is the tangent line of the border line 13 and thelimit. In the next text, the visual and convenient description, itstilled called the included angle between the central axis 33 and theborder line 13 or the limit, but the meanings of the central axis 33 andthe border line 13 are like that mentioned above, referring to thestraight segment of the border line 13 near the intersection point/limitor the extension direction or the tangent direction.

As mentioned above, the robot mover 11 is preferably symmetricallyprovided with two a border sensing element 35 on two sides of thecentral axis 33. As shown in FIG. 4, when the robot mower 1 collideswith the border line 13 and is not vertical to the border line 13, theleft side will collides with the border line 13 first, namely the leftborder sensing element 35 will sense collision with the border line 13first and sends a collision signal to the control module that representsthat the left side of the robot mower 11 collides with the border line13. The control module receives the left collision signal first andcorrespondingly judges that the robot mower moves to the border line 13from the left side of the intersection point of the border line 13 andthe robot mower 11, and the central axis 33 of the robot mower 11 formsan acute angle with the border line 13 on the left side of the collisionintersection point. Or, the border sensing element on one side firstsends a signal representing that it reaches a predetermined distancefrom the limit to the control module, and then the control module judgesthat the limit on one side of the central axis forms an acute angle withthe central axis. In other case, if the signal generated by the bordersensing element represents that the interior-exterior relationshipbetween the it and the limit, then the border sensing element on oneside first sends the signal representing that it goes out of the limitto the control module, and then the control module judges that the limiton one side of the central axis forms an acute angle with the centralaxis. After the moving direction of the robot mower 11, or theorientation relationship between the central axis 33 of the robot mower11 and the border line 13 during the collision is determined, the robotmower 11 correspondingly determines the turning direction and turnsright, namely the robot mower 11 turns in the direction to reduce theacute angle between the central axis 33 thereof and the border line 13.Or, as shown in FIG. 3, when the turn begins, the left side of the robotmower is closer to the limit, and then the robot mower turns clockwise;and if the right side is closer to the limit, then the robot mower turnsanticlockwise. Specifically, the control module of the robot mower 11controls the driving module, and then the rotation speed of the leftdriving wheel 23 is bigger than that of the right driving wheel 23, sothe robot mower 11 turns right and returns into the working scope 7. Inthis robot mower 11, the turning angle is fixed, greater than or equalto 90 degrees and less than 180 degrees, preferably a little greaterthan 90 degrees, between 90 degrees and 120 degrees. The reason that theturning angle is greater than or equal to 90 degrees is to ensure thatrobot mower 11 moves into the limit when the above mentioned acute anglevalue is undetermined. If this angle vale is determined, thecorresponding appropriate turning angle within 180 degrees can beselected according to the acute angle value, which is described indetail in the text below.

It should be noted that, the time of determining that the robot mower 11actually collides with the border line 13, so robot mower may cross theborder line 13 and then returns into the limit when performing turning.When crossing the border line 13, the other border sensing element 35 ofthe robot mower 11 may sense collision with the border line 13 and thensends the collision signal to the control module. As mentioned above,the border line 13 of the robot mower system is configured to be alittle closer to the inside of the lawn than the physical working scope,so the robot mower 11 does not exceed the actual physical working scopewhen turning.

As shown in FIG. 5, the extension direction of the border line 11 isdifferent from that in FIG. 4, so the turning direction is differenteven through the robot mower 1 faces the same direction. Specifically,the right side of the robot 11 collides with the border line 13 first,namely the right border sensing element 35 senses collision with theborder line 11 first, and sends a collision signal to the control moduleto represent that the right side of the robot mower 11 collides with theborder line. The control module receives the right collision signalfirst, and correspondingly determines that the robot mower moves towardsthe border line from the right side of the intersection point of theborder line and the robot mower, and the central axis of the robot mower11 forms an acute angle with the right border line of the collisionintersection point. After determining the moving direction of the robotmower 11 or the orientation relationship between the central axis 33 ofthe robot mower and the border line 13 during collision, the robot mower11 correspondingly determines the turning direction and anticlockwiseturns left, namely the robot mower 11 turns in the direction to reducethe acute angle between the central axis 33 and the border line 13.Specifically, the control module of the robot mower 11 controls thedriving module, so the rotation speed of the right driving wheel 23 isgreater than that of the left driving wheel 23, and the robot mower 11turns left to return into the working scope.

As shown in FIG. 6, the extension direction of the border line 13 isvertical to the moving direction of the robot mower 11 or the centralaxis 33 of the border line 13 during collision. At this moment, the twoborder sensing elements 35 of the robot mower 11 sends the collisionsignal to the control module, and the control module determines that therobot mower 11 vertically moves towards the border line and thencontrols the moving system to turn randomly.

The turning mode that the robot mower 11 and the border line 13 formdifferent angles are described above, and the angle variation of therobot mower 11 of the present invention in the typical turning processis described in the following text with reference to the FIG. 7.

As shown in FIG. 7, the moving track of the robot mower 11 crosses theborder line 13. The intersection point of the central axis 33 and theborder line 13 is O when robot mower 11 crosses the border line 13, andis P when the turn is completed and the robot mower goes back into thelimit. When the robot mower crosses the limit, the intersection point ofthe central axis 33 of the robot mower 11 or the moving track and oneside of the border line 13 form an acute angle O, as shown in thefigure. Then, the control module controls the robot mower 11 to turn inthe direction where the acute angle is reduced, and keep moving duringturning, leave the limit, return into the limit, and completes the turnafter going back into the limit. After the turn is completed, theintersection point of the central axis 33 of the robot mower 11 and theborder line 13 also forms an acute angle P, as shown in the figure. Theextension direction of one side of the angle P starting from P that islocated on the border line is opposite to that of the angle O startingfrom O that is located on the border line.

In the robot mower system, the predetermined location relationship fortriggering turning is that the predetermined distance is zero, so thetrack line is intersected with the border line. The peak of the includedangle between the central axis 33 of the robot mower 11 and the borderline 13 separates before and after the turning. But it is easilyunderstood that the track line translates vertically according to thedifferent predetermined distance, while the intersection point of thetrack line and the border line 13 changes, even is superposed ordisappears, but the two included angles between the central axis 33 andthe two border lines 13 are not changed. Simply speaking, each borderline 13 is divided into two sides extending in two directions from theintersection point of the central axis 33 and each border line 13 whenthe turning is triggered, and then the central axis 33 forms an acuteangle with one of the sides before turning and forms an acute angle withthe opposite other side extending in the other direction after turning.

If the robot mower 11 vertically collides with the border line 13, thenforms an acute angle with one of the sides after turning, and forms anacute angle with the opposite side extending in the other directionafter turning.

To better understand the present invention, the location variation ofthe robot mower 11 of the present invention in the typical turningprocess is described with reference to FIG. 8.

As shown in FIG. 8, one side of the robot mower 11 collides with theborder line first, and the other side of the robot mower 11 keeps acertain distance from the border line 13 during collision. As shown inthe figure, the distance is d₀. The robot mower 11 starts turning atthis moment. As mentioned above, if the left side collides with theborder line first, the robot mower 11 turns right; if the right sidecollides with the border line first, the robot mower 11 turns left,meaning if one of the sides collides with the border line first, therobot mower turns in the other side. Also as shown in the figure, thedistance from the side of the robot mower that collides with the borderline first to the border line 13 or the extension line of the borderline 13 is d₁, while the distance from the other side to the border line13 or the extension line of the border line 13 is d₂ when the turn iscompleted and the robot mower 11 enters the limit. As shown in thefigure, d₁ is smaller than d₂ after meaning that the robot mower 11keeps that the side colliding with the border line first closer to theborder line than the other side after the turn is completed.

Specifically, the limit detecting module sends a signal to the controlmodule when detecting that one side of the housing 21 and the limitreach the predetermined distance first, and the control module controlsthe driving module to bring the autonomous vehicle 1 to turn from oneside to the other side. When the turn is completed, the distance fromsaid one side of the autonomous vehicle 1 to the limit is smaller thanthat from said the other side to the limit.

From the above description it can be seen that, the included anglebetween the robot mower 11 keeping turning and the other side of theintersection point is also an acute angle, or the robot mower turns intothe working scope at a small angle which is at most 180 degrees on thepremise that the distance from one side of the robot mower that firstapproaches the border line to the limit is smaller than that from theother side to the limit. If the robot mower turns in the otherdirection, the turning angle is at least 180 degrees to reach theidentical final angle.

The above mentioned turning mode makes the robot mower 1 moves in adirection finally. If the working scope is divided into two parts by theline vertical to the limit at the intersection point of the autonomousvehicle 1 and the limit, then the autonomous vehicles moves from theoriginal part to another part after the turning instead of staying inthe original part. In this way, the autonomous vehicle frequentlycruises in different areas to increase the coverage efficiency of theworking scope, and more easily goes out of the complicated area.

In the above mentioned turning process, the determining of the limitdetecting module on the angle is qualitative, only determining whichside of the robot mower collides with the border line first; thencorrespondingly, the other side turns, and the turning angle does notexceed 180 degrees; or the limit detecting module only judges whichborder side of the intersection point 41 forms an acute angle with theautonomous mower 11, and then the robot mower 11 correspondingly turnsin the direction where the acute angle is reduced, finally forms anacute angle with the other side, and keeps moving straightly.

However, to achieve a better effect, the determining of the limitdetecting module on the angle is quantitative, namely monitoring thevalue of the included angle between the central axis of the robot mowerand the border line when the collision is determined. On this robotmower, the realization mode is as mentioned below:

The robot mower 11 is provided with a displacement monitoring elementfor monitoring the moving distance of the robot mower in a period oftime. The displacement and the speed are related parameters, so therobot mower 11 monitors the displacement of the robot mower throughmonitoring the moving speed. The displacement monitoring speedspecifically may be a speed sensor for monitoring the rotation speed ofthe driving wheels, or an acceleration speed for directly monitoring thespeed of the robot mower 11, or other elements capable of monitoring thespeed of the robot mower 11.

Before the turn is implemented actually, the two border sensing elements35 of the robot mower 11 collide with the border lines in succession andrespectively send the collision signals to the control module. Thedisplacement monitoring element monitors the displacement in the periodthat the border sensing elements collide with the border lines insuccession. Meanwhile, the distance between the two border sensingelements 35 is a known fixed value, so the included angles between therobot mower 11 and the border lines 13 can be calculated according tothe distance between the two border sensing elements and thedisplacement of the robot mower 11 when the two border sensing elements35 passes the border lines in succession. That is to say, the controlmodule records the moving distance of the autonomous moving distance inthe period of time when the two border sensing elements respectivelysend the signals representing that they reach a predetermined distancewith the limit, or the two border sensing elements respectively sendsignals representing that they cross the limit, and calculates the valueof the included angle between the central axis and the limit. Then, thecontrol module can correspondingly calculate an appropriate turningangle according to the included angle, make the robot mower 11 to keep afixed angle when leaving the border line or at variable angles. In thecase that the angle value can be calculated, the turning angle may besmaller than 90 degrees.

The signal of the island 15 is identical with that of the border line13, both of them are periodical current signals, so the robot mower 11determines the direction when colliding with the island 15 in a wayidentical to that when colliding with the border line 13 and leaves theisland 15 when turning.

No border line signal exists on the periphery of the obstacle 17, so therobot mower 11 cannot turn directly after finding the obstacle, butshall stop first, move back and then perform turning. However, theworking efficiency is reduced in this mode. Therefore, the robot mower11 can be also provided with a set of obstacle sensing modules forfinding the obstacle 17 before collision and perform turning.Preferably, the obstacle sensing modules can also monitor the angle ofthe robot mower 11 when colliding with the obstacle 17 so as to performturning in the mode similar to the mentioned case of collision withborder line 13, thus improving the efficiency. For example, the obstaclesensing modules can be an ultrasonic wave transmitting element installedon the robot mower 11 or two ultrasonic wave reducing elementsrespectively located on the two sides of the robot mower, judging thedistance from the obstacle and the angle through the difference betweenthe time that the two ultrasonic wave receiving elements on the twosides receive the reflected ultrasonic wave signals.

It should be noted that the mentioned specific turning structure andmode are only exemplary, and shall not limit the present invention.

As mentioned above, the determining of the limit detecting module on theangle may be qualitative or quantitive. Being qualitative refers to thatthe limit detecting module only judges which side of the intersectionpoint forms an acute angle with the autonomous vehicle 1, and then theautonomous vehicle 1 turns in the direction where the acute angle isreduced and keeps forming an acute angle with the other side afterturning. Being quantitive refers to that the limit detecting module candetermine the accurate angle between the autonomous vehicle and thelimit, and then the autonomous vehicle turns in a direction where theacute angle is reduced, and selects the turning angle according to thespecific turning angle to fulfill the aim of optimizing the turningangle. Optimizing the turning angle may refer to reducing the turning,ensuring that the springing angle in a certain scope, or optimizing thepath to increase the coverage rate or reduce the return times.

Also as mentioned above, the limit 3 may be various, a wall in a houseor other photo-optical signals, and shall not be limited to the currenttype border line signal or obstacle. Correspondingly, the limitdetecting modules vary with the property of the limit 3, such as theinfrared sensor, ultrasonic wave sensor, etc. Usually, the tangiblelimit can realize turning, and the autonomous vehicle cannot collidewith the limit, so the distance between the predetermined turning siteand the actual limit may be relatively long, and the sensor is theremote type to ensure no collision with the limit 3 during turning. Forthe signal type limit 3, the predetermined turning distance isrelatively short, and the autonomous vehicle turns when approaching oralready colliding with the border. Due to inertia, the real turningtrack may be intersected with the limit. Of course, the turningdetermining point of the signal type limit 3 may be set like that of thetangible limit, keeping a certain distance. Therefore, the autonomousvehicle is not intersected with the limit when turning, meaning that thedistance from the autonomous vehicle 11 to the limit is greater than orequal to 0 when turning.

As mentioned above, the ways for determining the distance and anglebetween the autonomous vehicle 1 and the border line are not limited tothose described in the specific embodiments, and may other others suchas the GPS navigation system similar to the car navigation and the imageacquisition technology. The memory of the control module is internallyprovided with the map of the working scope and the location anddirection of the border line, and the autonomous vehicle is internallyprovided with the GPS navigation module, and then the angle and distancecan be determined according to the map information and the GPSinformation when the autonomous vehicle collides with the border line,and then the mentioned turning mode is employed. The autonomous vehicleis equipped with a camera, and it is feasible to judge the collisiondirection and distance by identifying the image of the environment. Inthe present invention, the more important is to determine the turningstrategy and direction after turning.

For example, the robot mower 11 realizes the angle judgment and turningdirection determination through the border sensing elements on the twosides of the housing 21. However, it is also feasible through just oneborder sensing element 35.

The principle of determining the turning direction through one sensor isdescribed with reference to FIG. 9. The robot mower 11 crosses theborder line. After colliding with the border line, the turning angle ofthe robot mower 11 is fixed, so the turning track is basically fixed, asshown by the dotted line. However, the direction of the border line 13is unknown. The locations of three typical border lines 13 are shown inthe figure. Providing that the border lines 13 are vertical to themoving direction of the robot mower 11 or the central axis directionduring collision, and then the robot mower 11 forms an intersectionpoint O with the border line 13 when going out of the limit and theintersection point P when going back into the limit, and the moving pathof the robot mower 11 is an arc line OP. The length of the arc lien OPmay be a reference length for judging the angle relationship between thecentral axis and the border line 13 when the robot mower 11 collideswith the border line. If the robot mower 11 forms an acute angle withthe left side of the intersection point of the border line 13, then thetwo intersection points of the robot mower 11 are as shown by the arcline OA, and the length of OA is smaller than that of OP; if the robotmower 11 forms an obtuse angle with the left side of the intersectionpoint of the border line 13, the two intersection points of the robotmower 11 are as shown by the arc line OB, and the length of OB isgreater than that of OP. In this way, the angle relationship between therobot mower 11 and the border line 13 can be obtained by detecting themoving distance when the robot mower 11 goes out and goes into the limitand comparing the moving distance with OP. Then, corresponding actioncan be adopted, such as turning again when the moving distance isgreater than OP.

Specifically, when only one border sensing element 35 is available, therobot mower 11 moves towards the border line 13 until sensing that it islocated above the border line 13. At this moment, the border sensingelement 35 sends the collision signal to the control module. After thereceiving the collision signal, the control module sends an order to thedriving module to turn at a predetermined angle and move towards thelimit. In such circumstance, the control module cannot judge whetherthis turning direction is the direction where the non-obtuse anglebetween the central axis 33 of the robot 11 and the border line 13 isreduced, and the robot mower 11 keeps moving, so the border sensingelement 35 crosses the border to go outside. During turning or afterturning, the border sensing element 35 returns into the limit from theoutside, and passes the border line 13 from the above. The controlmodule records the time cost when the border sensing element crosses theborder line 13 twice, compares the time with one or more reference time,judges that the turning faces the acute angle between the central axis33 and the border line 13 when the robot mower 11 collides with theborder line if the time is smaller than a predetermined first referencetime, that the turning faces the direction where the right angle betweenthe central axis 33 and the border line 13 is reduced when the robotmower 11 collides with the border line if the time is equal to thereference time or is between two preference time, and that the turningfaces the direction where the obtuse angle between the central axis 33and the border line 13 is reduced when the robot mower 11 collides withthe border line if the time is greater than a preference time.

Judging the turning direction obtains the angle relationship between thecentral axis of the robot mower 11 and the border line 13 duringcollision, and the angle relationship between the direction of the robot11 and the border line 13 after turning. Then, the robot mower 11 canadopt the corresponding actions, for example controlling the robot mower11 to perform turning reversely on condition that the turning faces thedirection where the obtuse angle between the central axis 33 and theborder line 13 is reduced when the robot mower 11 collides with theborder line, so the moving direction of the robot mower 11 or thecentral axis 33 after turning form an acute angle with the border line13 which forms an obtuse angle with the central axis when the robotmower 11 collides with the border line.

To determine the relationship between the direction of the first turningand the original moving direction, optionally, the robot mower 11 isprovided with a displacement detecting element for detecting the movingdistance of the robot mower 11 at the interval that the border sensingelement 35 of the robot mower 11 crosses the border line twice,comparing the distance with one or more reference distances and thendetermines the turning direction. The process and direction are similarto those in comparison with the reference time and therefore are notdescribed in detail. Of course, the robot mower 11 can record the timeinterval of crossing the border line twice and the moving distance toincrease to the accuracy of judgment.

The mentioned turning method also keeps the robot mower moving in thewhole turning process, and the direction leaving the border line formingan acute angle with the border line 13 which forms an obtuse angle withthe central axis 33 when the robot mower 11 collides with the borderline. It is of directivity, obviously prior to the prior art.

It should be noted that the turning mode of the present invention isparticularly beneficial when passing through the narrow areas. FIG. 10and FIG. 11 are respectively path comparison diagrams of the autonomousvehicle passes through the narrow areas on condition that the pathplanning mode is not used and used, and the dotted line is the movingpath. It can be obviously seen that, it is very difficult for theautonomous vehicle 1 to leave the narrow area when the path planningmode is not used, and the autonomous vehicle 1 may luckily leave thenarrow after turning around; moreover, the leaving time is unknown. Ifthe path planning mode is employed, the autonomous vehicle 1 has adirection and can leave the narrow area after turning around for limitedtimes. Actual calculation shows that, in a typical narrow area, it costsan average time of 5 min for the autonomous vehicle to leave the narrowarea if the path planning mode is not used, and 30 s if the pathplanning method is used.

It also should be noted that, the common autonomous vehicle 1, no matterthe mower or dust collector, shall stop when encountering the limit 3and then can perform turning. Encountering the limit 3 is very frequent,which greatly affects the working efficiency of the autonomous vehicle1, resulting in that 15% of time is cost on braking/stopping and startupinstead of actual working. Besides, frequent startup and stop alsoaffect the service life of the mechanical elements of the autonomousvehicle 1 and waste energy. The autonomous vehicle 1 of the presentinvention can greatly reduce the stopping/braking times. During turningor from the autonomous vehicle moves towards the limit and reaches thepredetermined location relationship to end of the turning, theautonomous vehicle keeps moving or the driving motor keeps driving thewheel set, thereby greatly improving the overall efficiency of themower, saving energy, protecting the environment, prolonging the servicelife of the battery, and cutting more grasses or doing more work in aunit time.

Statistically, the autonomous vehicle 1 can do 20% of extra work on thesame condition of full power after the path planning mode is employed,effectively using the inertia thereof and achieving a very goodenergy-saving effect. Meanwhile, in the same working time, the movingdistance of the autonomous vehicle adopting the path planning mode is35% greater than that of the autonomous vehicle not adopting the pathplanning mode, so the working efficiency is greatly improved. To improvethe working efficiency to the maximum extent, the autonomous vehicle 1has such a mode in which the mower always keeps moving and never stopsduring turning when carrying out the work tasks. Of course, thementioned turning mode may be one of a plurality of the path planningmodes of the autonomous vehicle. The autonomous vehicle enables thismode only when detecting that it locates in the narrow area or cornerarea. The detecting mode may be: quickly colliding with the border forseveral times, or colliding the border line for predetermined times in apredetermined time period.

To obtain the optimized path, in particular to further optimize thespeed of leaving the narrow area, the specific embodiment of the presentinvention also provides another path planning mode. Such path planningmode makes the autonomous vehicle quickly leave the narrow area bymoving along the limit 3 for a distance after encountering the limit 3.After approaching the limit 3, the autonomous vehicle rotates slightlyfirst to adjust the moving direction to be consistent with the extensiondirection of the limit 3, then moves at a predetermined distance alongthe extension direction of the limit 3, and turns towards the limit 3again. After the turn begins and before the turn is completed, theautonomous vehicle moves for a distance. The specific way of moving fora distance may be that the autonomous vehicle moves for a predeterminedtime or a predetermined distance, and the predetermined distance is 20cm-100 cm.

FIG. 9 is a schematic view of the moving path of the robot mower 11adopting the path planning mode. As shown in FIG. 12, similarly, therobot mower 11 has border sensing elements 35 located on two sides ofthe housing 21. After moving for a distance, the robot mower 11 collideswith the border line 13. In the case of non-vertical collision, oneborder sensing element 35 collides with the border line first and sendsthe collision signal to the control module. The control modulecorrespondingly judges the angle relationship between the central axis33 of the robot mower 11 and the border line 13, then gives an order tothe driving module to turn in a direction where the acute angle or rightangle between the central axis 33 and the border line 13 is reduced.During or after turning, the border sensing element 35 which previouslycrossed the border line 13 moves back into the limit, while the otherborder sensing element 35 still locates out of the limit. The robotmower stops turning and starts to move along the border line 13.

When the robot mower moves along the border line 13, the control modulecorrects the moving direction at any time to ensure that the mentionedone border sensing element 35 locates in the limit and the mentionedother border sensing element 5 locates out of the limit, namely ensuringthe magnetic fields of two electric inductors are opposite. In this way,the robot mower 11 always locates in the limit on one side, and out ofthe limit on the other side, realizing moving cross and along the borderline 13. When a certain side of the robot mower 13 moves out of thelimit or into the limit, the magnetic fields sensed by the two electricinductors are identical, and the robot mower correspondingly rotatesslightly in a direction to make the side move back into or out of thelimit, so the magnetic fields sensed by the two electric inductors arekept opposite. In this way, the control module controls the drivingmodule to keep the distances between the two electric inductors and theborder lines equal. However, the mentioned mode of moving across theborder line and the quantity of the electric inductors are notnecessary. As long as the control module controls the driving module tokeep the distances from the electric inductors to the border linesunchanged, the autonomous vehicle can also move along the border line.The distance may be 10 cm. In this occasion the autonomous vehiclesmoves on the border line.

To make the moving path along the border line straighter and improve themoving efficiency, preferably, the control module but only monitors theintensities, but also the directions of the magnetic fields sensed bythe two electric inductors, and keeps the directions of the magneticfields sensed by the two electric inductors opposite and intensitiesequal. In this way, the distances from the two electric inductors to theborder lines 13 are kept equal, realizing that the robot mower 11 movesalong the straight line. When the moving direction of the robot mower 11deviates from the extension direction of the border line 13, theintensities of the magnetic fields sensed by the two electric inductorsbecome different, and the robot mower 11 correspondingly rotatesslightly towards the direction where the intensities of the magneticfields sensed by the two electric inductors are identical, so themagnetic fields sensed by the two electric inductors are kept identicalin intensity and opposite in direction.

After moving for a predetermined distance along the border line, thecontrol module of the robot mower 11 orders the driving module toperform turning again to leave the border line 13 and move back into thelimit. The turning direction towards the direction of the first turning,and the turning angle is smaller than or equal to 90 degrees.

The mentioned turning mode approximately has three steps: turning forthe first time, moving along the border line, and turning for the secondtime. However, omitting the first step is also feasible, meaning thatthe robot mower 11 directly moves along the border line after collidingwith the border line. The effect of the first turning is achieved bycorrecting the direction of moving along the border line.

The above mentioned specific turning and turning process are exemplary,and can have variations.

For example, the limit 2 may be a border or an obstacle. The border maybe a lead with a current signal, a physical border, or other bordersformed by acoustic and optical signals.

For another example, when judging collision with the border line orreaching a predetermined distance away from the limit 3, the includedangle between the central axis 33 in the autonomous vehicle 1 and thelimit 3 may be the border sensing elements 35 on the sides in thisembodiment, the GPS navigation system or other feasible systems.

For another example, the way of moving along the border line may moveacross the border line in this embodiment, or move for a predetermineddistance against the border line. The predetermined distance for movingalong the border line is preferably 20-100 cm in this embodiment, butcan be correspondingly according to the working property of theautonomous vehicle 1 and the size, shape and features of the map, orfreely set by the operator.

Through moving for a distance along the border line 13 and leaving theborder line along the original direction, the autonomous vehicle 1further improves the efficiency of leaving the narrow areas. As shown inFIG. 8 and FIG. 9, the turning times and moving distance for leaving thenarrow area are smaller in the mode of moving along the border linefirst and then perform turning.

1. An autonomous vehicle, for moving and working in a working scopedetermined by a limit, comprising a housing having a longitudinalcentral axis; a driving module for driving said autonomous vehicle tomove and to make a turn being mounted in said housing, said drivingmodule comprises a wheel set and a driving motor for driving the wheelset to move; a limit detecting module for detecting a locationrelationship between said autonomous vehicle and said limit beingmounted in said housing; an energy module for providing energy for saidautonomous vehicle being mounted in the housing; and a control moduleelectrically connected with said driving module and said limit detectingmodule; said autonomous vehicle makes a turn to leave away the limitafter driving to the limit and reaching a predetermined locationrelationship, where the limit is divided into one side and another sideby the central axis, wherein said control module controls said drivingmodule to perform a turning operation according to a signal representingsaid angle relationship between said autonomous vehicle and said limit,said signal being transmitted from said limit detecting module, so thatsaid central axis of said autonomous vehicle always forms an acute angleor a right angle with said one side of said limit when said turningoperation is completed, said another side of said limit forms an acuteangle or a right angle with said central axis of said autonomous vehiclewhen said turning operation starts. 2-32. (canceled)